This Program Project constitutes an effort to reduce the study of mutation rates in human germ cells and somatic cells in vitro to the protein level, employing a variety of new technologies. With respect to germ cells, electrophoresis employing the O'Farrell two-dimensional acrylamide gel technique will be used to separate the protein constituents of leucocytes, erythrocytes, and human plasma. The various modifications of this introduced by N. and L. Anderson to facilitate large-scale gel processing will be utilized. Computer programs will be developed for the reading and scoring of these gels. An especial challenge here is the development of algorithms which will permit the rapid analysis of the digitized information on each gel for significant abnormality in the complicated pattern. A variety of approaches to validating the ability of this technique to detect genetic variants will be employed. A particular effort will be directed towards developing conventional electrophoretic systems for studying specific leucocyte enzymes, variants of which can then be used to validate the two-dimensional system. Finally, an effort will be made to use protein markers such as lactate dehydrogenase, elongation factor-2 and carbonic anhydrase in studies of in vitro somatic cell mutation rates. Special cell lines will be developed for these studies. Ultimately, we hope to approach the study of mutation in human somatic cells in culture by the same techiques being developed for the study of germ cell mutation.